Shrews are small mammals of the family Soricidae spread all over the world and divided into 28 different genres. The most numerous of these, Crocidurahas a record: it includes 197 species, the highest number ever among mammals; and despite having no representatives in the United States, it is one of the most present genres throughout the world, from Europe to Africa to East Asia.
Until recently, these shrews were also widespread in Australia, but now the IUCN gives us some bad news: Crocidura trichurathe Christmas Island shrew, the only one on the Australian continent, is officially extinct.
An identikit of the shrew. Crocidura trichata it is (was) endemic, as its name suggests, to the small Christmas Island, which is located south of Indonesia, but which politically belongs to Australia, despite being more than 1,500 km away from the continent. A few centimeters long and weighing around 5 grams, these small shrews were characterized by a particularly long tail for the genus, and above all by the difficulty of studying them: very few photos exist of them, they were rarely observed in nature and, between 1958 and 1985, they had disappeared from circulation.
Rare sightings. Not extinct, though: it was simply impossible to find them. It’s not clear what the main cause is of a decline that began at the beginning of the last century, but the clues all point in the usual directions: habitat destruction, predation by invasive species (e.g. cats and rats), and even, according to some studies, the inadvertent introduction of the yellow crazy ant, one of the most invasive ant species in the world.
Whatever the precise causes (most likely a combination of these elements), Christmas Island shrews have been ghosts for years.
EXTINCT. Now comes the official announcement from the IUCN: we haven’t seen one since 1984 Crocidura trichataand the species is considered officially extinct; there is a lot of evidence of this fact, but the most evident is that no traces of it have been found in the bellies of the hundreds of stray cats that have been euthanized in recent decades on Christmas Island. It is therefore possible that the extinction of these shrews occurred ten or even twenty years ago, and that we have only “noticed” it now: the last hope of conservation experts is that these assessments turn out to be wrong, and that sooner or later we will “catch” one of these shrews again.
The massacre of mammals. Beyond the news itself (the extinction of a species is always a tragedy), the disappearance of the Christmas Island shrews is indicative of a worrying trend that has involved Australia for a long time: its mammals are becoming extinct at a higher rate than those of other countries, and from 1788 to today we have witnessed the disappearance of 39 species, 10% of all those of terrestrial mammals present in Italy before the arrival of the first settlers.
A continuous disaster, which the government is finally taking action to stop. The hope is that this destructive trend can be reversed.
